Awesome gift
!
The Dreamcast doesn't really have parts that need pro-active attention. The only thing you might want to replace is the internal CMOS battery, this one is most likely dead resulting in the DATE/TIME not saving. This does not impact playability at all, its just annoying to have to enter the DATE/TIME everything you use it.
Recap or new PSU is not needed, unless you're experiencing problems. That being said, I would recommend installing a GDEMU as replacement to the GD-DRIVE. Having pretty much zero loading times and the ability to play games without swapping/inserting discs is a great luxury.